I've been playing around with the idea of subdomains as minisites and have finally gotten it working. Mini-sites go back to the days of page-rank as King of SEO, and Michael Campbell (Striking it Niche, Nothing but 'Net, etc.). The idea is that you would build mini-sites around your niche and people would find all sorts of fascinating content within that mini-site and they'd bounce all around within it and build up your pagerank, making your SERPs improve.

Then you'd link these mini-sites together and you'd have a mini-web. Since the links were by related content, you could actually take over a major niche just on pagerank.

But the days of pagerank are ebbing, if not gone. Google doesn't think that metric is as important these days.

However, the concept is a fascinating one. It allows you to group your content by niche and then cross-link to related content on another site you also created and maintain. So link love can still be shared, along with subscribers (if you liked this blog post, other readers also found these blog-posts fascinating...).

Enter the idea of sub-domains. Now for the time being, Google still gives subdomains individual pagerank and treats them basically as their own site. Meaning that when you link from one subdomain to another, you are crosslinking sites. So you are giving authority to another of your own sites.

But this has been tricky to do, since other than hand-coding mini-sites, the best way to build a site was with WordPress (or some other CMS scripting platform). Meaning that if you wanted to set up a subdomain and install WP on it, you'd have several installs on your hard-drive with multiplicitous files duplicated in every subdomain.

Enter WordPressMU. (Multi-User.) It has the option of being able to create new blogs and assigning them a subdomain name - used on WordPress.com and many others. So each person runs a single blog, but the underlying program really runs them all as one huge mega-blog.

Here's the deal: Set up WPMU on a host and then create a new "blog" for each keyword niche. Posts in that blog are all germain to that subject and so build authority within that subdomain. Every subdomain is it's own subject - and so you actually build mini-sites again - and a mini-web, after a fashion.

What makes this really take off is that you can have completely separate look and feel for every sub-domain blog. It looks like it's own blog - which it is. And templates make it much, much easier to configure - but far more powerful - than mini-sites.

The great part about it is that I can build an opt-in mail list just for that book (coming today, I hope) and so get subscribers on this particular niche completely independent of the other books I write/edit/(re)publish. Also, I'm not limited by a single template's foibles, but can actually grab and install various templates until I have the one which is appropriate to that particular niche. (A person looking to solve their "I've-just-been-scammed-by-a-telemarketer" problem will expect a more dramatic look and feel than the "I'd-like-to-lose-more-weight" person - who needs more reassurance.)

In short, WPMU looks to solve a variety of problems with a single install. Sure, there are some tricks that have to be mastered, but it's not a particular problem compared to learning HTML and coding pages by hand.